室内MIMO可见光通信的接收特性

建立了一种基于MIMO的室内二次反射可见光通信的信道模型。通过模型仿真,从不同位置处接收面上探测器的不同间距、不同面积以及接收面横向、纵向旋转方面,分析了室内MIMO可见光通信的接收特性。仿真结果表明,在满足信号可恢复的条件下,接收面探测器间距d的变化对光信号接收的影响很小,不同接收位置的接收信噪比(SNR)也呈现不同的分布。另外,接收面横向旋转不会影响光信号接收,而纵向旋转具有一定的限制范围。     

电荷耦合器件的γ辐照剂量率效应研究

对电荷耦合器件进行了不同剂量率的γ辐照实验,通过多种参数的测试探讨了剂量率与电荷耦合器件性能退化的关系,并对损伤的物理机理进行分析。辐照和退火结果表明:暗信号和暗信号非均匀性是γ辐照的敏感参数,电荷转移效率和饱和输出电压随剂量累积有缓慢下降的趋势;暗场像素灰度值整体抬升,像元之间的差异显著增加;电荷耦合器件的暗信号增量与剂量率呈负相关性,器件存在潜在的低剂量率损伤增强效应。分析认为,剂量率效应是由界面态和氧化物陷阱电荷竞争导致的。通过电子-空穴对复合模型、质子输运模型和界面态形成对机理进行了解释。     

基于VISA的PXI设备访问新方法

由于PXI设备的灵活性,在访问过程中需要用户参与到配置过程中。为了方便用户,并增强PXI设备访问的安全性和准确性,避免系统因用户配置问题导致的功能异常,提出了一种基于VISA的以PXI设备串号为基础的设备访问方法。通过将PXI设备的串号信息固化在PXI设备的配置寄存器中,根据设备串号信息自动获得设备资源描述符,进而对设备进行访问。实际应用表明,该方法能够完成对PXI设备的访问,避免了用户的配置过程,实现了PXI设备资源的自动配置,增强了设备访问的安全性和准确性,具有良好的实际应用价值。     

CCD纵向抗晕结构研究

建立了电荷耦合器件(CCD)纵向抗晕结构模型,运用半导体器件二维数值模拟软件MEDICI,对建立的纵向抗晕CCD器件模拟结构进行数值计算,并详细分析和讨论了衬底反偏电压、1PW层硼掺杂浓度、n型沟道磷掺杂浓度和TG转移栅下P杂质掺杂浓度等参数对CCD纵向抗晕能力的影响,得到了CCD纵向抗晕结构的一种优化结构.     

GaN功率器件模型及其在电路设计中的应用

介绍了建模软件的结构和采用的新模拟方法,详细阐述了建模软件中所采用的模型以及方程,利用自主开发的窄脉冲测试系统测试GaN HEMT器件的Ⅰ-Ⅴ特性,并用国外先进仪器测试S参数,准确地建立GaN HEMT器件的非线性模型.建模结果在ADS软件中得到验证,并用于GaN功率单片的设计中,在生产中起到了一定的指导作用.     

有机薄膜发光器件的研究进展

有机薄膜电致发光器件具有发光效率高、驱动电压低、功耗小、响应速度快等优点,已成为近年来显示技术领域的研究热点.基于有机发光器件的能级结构,分析了电极、有机薄膜以及界面三者对器件性能的影响及相应的改进措施.重点介绍了有机发光材料的研究进展,简要介绍了国内外在有机电致发光显示方面的最新进展.     

Rapid discrimination of single-nucleotide mismatches using a microfluidic device with monolayered beads

A microfluidic device incorporating monolayered beads is developed for the discrimination of single-nucleotide mismatches, based on the differential dissociation kinetics between perfect match (PM) and mismatched (MM) duplexes. The monolayered beads are used as solid support for the immobilization of oligonucleotide probes containing a single-base variation. Target oligonucleotides hybridize to the probes, forming either PM duplexes or MM duplexes containing a single mismatch. Optimization studies show that PM and MM duplexes are easily discriminated based on their dissociation but not hybridization kinetics under an optimized buffer composition of 100 mM NaCl and 50% formamide. Detection of single-nucleotide polymorphism (SNP) using the device is demonstrated within 8 min using four probes containing all the possible single-base variants. The device can easily be modified to integrate multiplexed detection, making high-throughput SNP detection possible.     

Optimal control for the thermistor problem with a current limiting device

Email: cimatti{at}dm.unipi.it Received on September 26, 2005; Accepted on August 2, 2006 The problem of finding in the thermistor problem the optimaldifference of applied potential in order to minimize a suitablecost functional involving the temperature is studied. We findthe optimal system in the elementary case of constant electricconductivity. In addition, a theorem of existence of the optimalsolution is given in the general case of conductivities dependingon the temperature.     

A multiserver retrial queue: regenerative stability analysis

We consider a multiserver retrial GI/G/m queue with renewal input of primary customers, interarrival time τ with rate , service time S, and exponential retrial times of customers blocked in the orbit. In the model, an arriving primary customer enters the system and gets a service immediately if there is an empty server, otherwise (if all m servers are busy) he joins the orbit and attempts to enter the system after an exponentially distributed time. Exploiting the regenerative structure of the (non-Markovian) stochastic process representing the total number of customers in the system (in service and in orbit), we determine stability conditions of the system and some of its variations. More precisely, we consider a discrete-time process embedded at the input instants and prove that if and , then the regeneration period is aperiodic with a finite mean. Consequently, this queue has a stationary distribution under the same conditions as a standard multiserver queue GI/G/m with infinite buffer. To establish this result, we apply a renewal technique and a characterization of the limiting behavior of the forward renewal time in the (renewal) process of regenerations. The key step in the proof is to show that the service discipline is asymptotically work-conserving as the orbit size increases. Included are extensions of this stability analysis to continuous-time processes, a retrial system with impatient customers, a system with a general retrial rate, and a system with finite buffer for waiting primary customers. We also consider the regenerative structure of a multi-dimensional Markov process describing the system. This work is supported by Russian Foundation for Basic Research under grants 04-07-90115 and 07-07-00088.     

智能型高速CCD相机的时序电路的研制

首先详细地介绍了几种传统时序电路的实现方法与各自存在的优缺点 ,然后对 isp L SI器件的性能特点以及 TDI- CCD相机的组成结构、工作原理进行了简要地阐述 ,最后对采用 isp L SI器件实现 CCD相机时序电路的全过程进行了全面、细致地分析。本文结合实际课题 ,已由在线可编程大规模逻辑器件实现了高速 TDI- CCD相机的时序电路。此相机系统具有一些重要参数 (行周期、TDI级数、视频信号的增益、偏置参数 ) ,并可以灵活控制。同时该系统又具有高可靠性、高稳定性、低功耗等特点。